Just got off a 10 day Panama Canal cruise on the Brilliance. You have selected an absolutely beautiful ship. You should not have to worry about any of the E3 cabins on Deck 7. They are very nice size rooms and they are designed for maximum utilization of space. Since you will be above the main public deck with staterooms above you - noise should not be an issue.
Nancy

We went on Brilliance and stayed in the E1 cabins on deck 7, not what we had originally booked but were upgraded, what a great surprise. The E1 cabins on that deck have a balcony that is about double the size of other balconies.(Look at a picture of that deck and you can see the bigger balconies) We did not have any problem with noise on that deck and we are leaving on Jan 24 for the 11-night E.Carribean and specifically reserved on Deck 7 again.